This topic has been discussed several times in the past, if you do a forum search, you should able to find them. The schematic that you showed appears to be copied from somewhere, but it’s basically the same as the one that is shown here (near the bottom of the page): Practical Tone Controls.
Some people like to do things the hard way...
Hard work never killed a man
Yes I have, I just change the pot value to 100k rather 10k and on the simulator looks like much better response, if you can add more better option much appreciate it.....all the best
Thanks cerrem, that is what exactly I was thinking about, in fact I add to the original schematic of Practical Tone Control an output amplifier, but I do not know if is right how I did it, can you suggest something more specific?
Thanks wavebourn, can you suggest a better tube? What about 6N2P-EV?..all the best
no prob I appreciate your moral support.....all the best
Thank you, is very similar to the Practical Tone Control schematic but with a 100k pot.....all the best
Unexpected arrival of shipping from US during lockdown of remaining parts necessary to finish this all tube graphics EQ by Rickard Berglund suggested here by DEMETRIOS then again extended quarantine until May 15 so perfect for give a finish to this project.
Big task has been find a way to avoid to much cable connections, so I made this kind of "guitar string" for connect the all 10 modules, this workout very well avoiding bundles of wires and unwanted oscillations.
I just tested musically and sound and work very very well, no oscillation whatsoever and even the little hum on the wooden board test is gone, max vol on amp and no noise at all.
I still need nice knobs and somehow some print for the front panel.
I will test now the EQ with generator, scope and Rew for see the real performance.....all the best
Attached Thumbnails
Big task has been find a way to avoid to much cable connections, so I made this kind of "guitar string" for connect the all 10 modules, this workout very well avoiding bundles of wires and unwanted oscillations.
I just tested musically and sound and work very very well, no oscillation whatsoever and even the little hum on the wooden board test is gone, max vol on amp and no noise at all.
I still need nice knobs and somehow some print for the front panel.
I will test now the EQ with generator, scope and Rew for see the real performance.....all the best
Attached Thumbnails
Attachments
Thank you for your comment, there is 10 channel but one valve for the channel 1kHz is fixed on the bottom of the chassis close to the guitar string, there was absolutely no more space...
The bargraph is not connected to the audio source, I used a 3 gang 100K potentiometer, 2 gang for the 2 EQ channel and 1 gang for the display that is completely independent but perfectly tuned with the rotation of the potentiometer.....all the best
Thank you for your comment, there is 10 channel but one valve for the channel 1kHz is fixed on the bottom of the chassis close to the guitar string, there was absolutely no more space...
The bargraph is not connected to the audio source, I used a 3 gang 100K potentiometer, 2 gang for the 2 EQ channel and 1 gang for the display that is completely independent but perfectly tuned with the rotation of the potentiometer.....all the best
Nice construction !
What about the sound quality ?
Hi Demetrios,
Sound quality is extremely good and exactly what I was expected, the equalisation is very smooth and gentle, 5/6 dB boost or cut, THD 0.090% measured, no noise or hum whatsoever, death silent.
But the journey has been not so easy, first I replace 12AX7 with 6N2P-EV more reliable and performing, then on prototype test realise how long wires also not shielded was a real problem and every small details on the build count then I complicate the all project with the add of the led bar graph, so all together takes more than one year to complete the project, actually you were the fist suggest this EQ
and I am now very very happy. Next project will be the "Blonder-Tongue Audio Baton", that is a different approach on EQ of the tube era with a more sharp response, so I keep myself busy.....all the best to you and keep yourself safe.....ciaooooo
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